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Abstract: Wind erosion and accumulated sand are recognized as the primary forms of cropland desertification in the arid and semiarid region, Inner Mongolia. However, there is a lack of knowledge on the effects of wind erosion and accumulated sand on soil properties and crop growth properties in this region. A field experiment was conducted from 2001 to 2002 on desertified cropland with gradients of wind erosion and accumulated sand to investigate changes in soil and crop growth properties resulting from desertification in the Horqin sandy land. Results indicated that the soil environment degraded significantly and crop growth and biomass were seriously restrained by wind erosion. In the severely eroded cropland, soil clay, organic matter, total N and P, available N and P, average soil moisture decreased by 59.6%, 71.2%, 67.4%, 31.4%, 64.5%, 38.8% and 51.8%, respectively. Erosion increased soil pH from 8.66 to 8.92; delayed plant life cycle by 6 days, decreased plant height and diameter by 15.5% and 29.1%, and decreased above and below ground biomass and seed yield by 87.3%, 47.9% and 96.5%, respectively. Effects of a little accumulated sand were fewer on soil properties and crop growth and seed yield compared to wind erosion, severe accumulated sand effects on the cropland remain to be studied further. The results of correlation analysis showed that crop biomass and seed production were significantly correlated to organic matter, total N, pH and soil moisture under circumstance of worsened soil environment. In the windy and sandy region in Inner Mongolia, some measures to control cropland erosion should be introduced including construction of windbreak, stubble cultivation, increased organic fertilizer and spring irrigation. [Copyright &y& Elsevier]

Abstract: In the Horqin Sand Land, more than half of the original pasture area has been converted to farmland over the last century. A field experiment was conducted from 2000 to 2001 on five croplands in the Horqin Sand Land of Inner Mongolia to examine differences in soil properties, crop productivity and irrigation effects across different soils in the region to assess their relative suitability for cultivation, in the face of continued pressure for conversion of these generally fragile, sandy soils to agriculture. Two irrigated croplands studied were originally sandy meadow (ISM) and sandy grassland (ISG), and three dry croplands were from sandy meadow (DSM), sandy grassland (DSG) and fixed sand dunes (DFD). Results showed that most measured properties of soils, and crop productivity, differed among the five croplands. The silt+clay fraction, bulk density, organic matter content, total N and P, available N and P, average soil moisture and temperature, plant height and aboveground biomass were as follows in the DSM|DSG|DFD soils: 51.1%|47.5%|24.3%; 1.44g/cm3|1.49g/cm3|1.58g/cm3; 6.3g/kg|4.6g/kg|3.4g/kg; 0.55g/kg|0.33g/kg|0.21g/kg; 0.21g/kg|0.17g/kg|0.13g/kg; 27.0mg/kg|13.7mg/kg|7.7mg/kg; 2.9mg/kg|2.9mg/kg|3.0mg/kg; 9.4%|7.0%|6.2%; 21.4°C|21.7°C|22.0°C; 225cm|220cm|181cm; and 2116g/m2|1864g/m2|1338g/m2. Corresponding values for ISM|ISG soils were: 54.3%|47.9%; 1.42g/cm3|1.49g/cm3; 8.5g/kg|6.4g/kg; 0.58g/kg|0.42g/kg; 0.20g/kg|0.19g/kg; 29.0mg/kg|23.3mg/kg; 4.7mg/kg|7.9mg/kg; 13.0%|10.1%; 21.0°C|21.1°C; 266cm|245cm; and 2958g/m2|2702g/m2. In general, the ecological origin of a cropland was a stronger determinant of its current characteristics than was irrigation history, although irrigation was correlated with significantly increased organic matter content, some soil nutrient levels, and aboveground biomass productivity. Results indicate that fixed sand dunes should not be converted to cropland because of their very sandy and poorer soil, lower biomass productivity and greater wind-erosion risk. Although both the sandy meadow and sandy grassland may be reclaimed for farming, the cropland derived from the sandy meadow had higher resistance to wind erosion and higher crop productivity, so is somewhat more suitable than sandy grassland. [Copyright &y& Elsevier]